Big Show is pissed at Sheamus constantly mentioning that Show's last world title reign was 45 seconds long, so Show challenged the person who defeated him for the title to a match to prove his 45-second loss was in fact a fluke and driven by the MITB briefcase more than anything else.

FirstNationalBastard:TheManofPA: Are we forgetting too that DBD beat Big Show in a cage? I swear that match ended on a botch, but damn if it didn't result in DBD making it to EC and then stunningly WM

...for 18 seconds.

Yeah, but that lead to the DBD and YES YES YES thing really taking off to spite Vince for the 18 seconds decision. If that never happens, Vince just immediately shows DBD to the midcard and then Superstars. I believe if not for the botch, we get a more heelish Show-Irish at WM with no DBD on the card (or maybe the dark match again)